libvpx: Pull from upstream

source/libvpx/vp9/decoder/vp9_thread.c

-// Copyright 2013 Google Inc. All Rights Reserved.
-//
-// Use of this source code is governed by a BSD-style license
-// that can be found in the COPYING file in the root of the source
-// tree. An additional intellectual property rights grant can be found
-// in the file PATENTS. All contributing project authors may
-// be found in the AUTHORS file in the root of the source tree.
-// -----------------------------------------------------------------------------
-//
-// Multi-threaded worker
-//
-// Original source:
-//  http://git.chromium.org/webm/libwebp.git
-//  100644 blob 08ad4e1fecba302bf1247645e84a7d2779956bc3  src/utils/thread.c
-
-#include <assert.h>
-#include <string.h>   // for memset()
-#include "./vp9_thread.h"
-#include "vpx_mem/vpx_mem.h"
-
-#if CONFIG_MULTITHREAD
-
-struct VP9WorkerImpl {
-  pthread_mutex_t mutex_;
-  pthread_cond_t  condition_;
-  pthread_t       thread_;
-};
-
-//------------------------------------------------------------------------------
-
-static void execute(VP9Worker *const worker);  // Forward declaration.
-
-static THREADFN thread_loop(void *ptr) {
-  VP9Worker *const worker = (VP9Worker*)ptr;
-  int done = 0;
-  while (!done) {
-    pthread_mutex_lock(&worker->impl_->mutex_);
-    while (worker->status_ == OK) {   // wait in idling mode
-      pthread_cond_wait(&worker->impl_->condition_, &worker->impl_->mutex_);
-    }
-    if (worker->status_ == WORK) {
-      execute(worker);
-      worker->status_ = OK;
-    } else if (worker->status_ == NOT_OK) {   // finish the worker
-      done = 1;
-    }
-    // signal to the main thread that we're done (for sync())
-    pthread_cond_signal(&worker->impl_->condition_);
-    pthread_mutex_unlock(&worker->impl_->mutex_);
-  }
-  return THREAD_RETURN(NULL);    // Thread is finished
-}
-
-// main thread state control
-static void change_state(VP9Worker *const worker,
-                         VP9WorkerStatus new_status) {
-  // No-op when attempting to change state on a thread that didn't come up.
-  // Checking status_ without acquiring the lock first would result in a data
-  // race.
-  if (worker->impl_ == NULL) return;
-
-  pthread_mutex_lock(&worker->impl_->mutex_);
-  if (worker->status_ >= OK) {
-    // wait for the worker to finish
-    while (worker->status_ != OK) {
-      pthread_cond_wait(&worker->impl_->condition_, &worker->impl_->mutex_);
-    }
-    // assign new status and release the working thread if needed
-    if (new_status != OK) {
-      worker->status_ = new_status;
-      pthread_cond_signal(&worker->impl_->condition_);
-    }
-  }
-  pthread_mutex_unlock(&worker->impl_->mutex_);
-}
-
-#endif  // CONFIG_MULTITHREAD
-
-//------------------------------------------------------------------------------
-
-static void init(VP9Worker *const worker) {
-  memset(worker, 0, sizeof(*worker));
-  worker->status_ = NOT_OK;
-}
-
-static int sync(VP9Worker *const worker) {
-#if CONFIG_MULTITHREAD
-  change_state(worker, OK);
-#endif
-  assert(worker->status_ <= OK);
-  return !worker->had_error;
-}
-
-static int reset(VP9Worker *const worker) {
-  int ok = 1;
-  worker->had_error = 0;
-  if (worker->status_ < OK) {
-#if CONFIG_MULTITHREAD
-    worker->impl_ = (VP9WorkerImpl*)vpx_calloc(1, sizeof(*worker->impl_));
-    if (worker->impl_ == NULL) {
-      return 0;
-    }
-    if (pthread_mutex_init(&worker->impl_->mutex_, NULL)) {
-      goto Error;
-    }
-    if (pthread_cond_init(&worker->impl_->condition_, NULL)) {
-      pthread_mutex_destroy(&worker->impl_->mutex_);
-      goto Error;
-    }
-    pthread_mutex_lock(&worker->impl_->mutex_);
-    ok = !pthread_create(&worker->impl_->thread_, NULL, thread_loop, worker);
-    if (ok) worker->status_ = OK;
-    pthread_mutex_unlock(&worker->impl_->mutex_);
-    if (!ok) {
-      pthread_mutex_destroy(&worker->impl_->mutex_);
-      pthread_cond_destroy(&worker->impl_->condition_);
- Error:
-      vpx_free(worker->impl_);
-      worker->impl_ = NULL;
-      return 0;
-    }
-#else
-    worker->status_ = OK;
-#endif
-  } else if (worker->status_ > OK) {
-    ok = sync(worker);
-  }
-  assert(!ok || (worker->status_ == OK));
-  return ok;
-}
-
-static void execute(VP9Worker *const worker) {
-  if (worker->hook != NULL) {
-    worker->had_error |= !worker->hook(worker->data1, worker->data2);
-  }
-}
-
-static void launch(VP9Worker *const worker) {
-#if CONFIG_MULTITHREAD
-  change_state(worker, WORK);
-#else
-  execute(worker);
-#endif
-}
-
-static void end(VP9Worker *const worker) {
-  if (worker->status_ >= OK) {
-#if CONFIG_MULTITHREAD
-    change_state(worker, NOT_OK);
-    pthread_join(worker->impl_->thread_, NULL);
-    pthread_mutex_destroy(&worker->impl_->mutex_);
-    pthread_cond_destroy(&worker->impl_->condition_);
-#else
-    worker->status_ = NOT_OK;
-#endif
-  }
-  vpx_free(worker->impl_);
-  worker->impl_ = NULL;
-  assert(worker->status_ == NOT_OK);
-}
-
-//------------------------------------------------------------------------------
-
-static VP9WorkerInterface g_worker_interface = {
-  init, reset, sync, launch, execute, end
-};
-
-int vp9_set_worker_interface(const VP9WorkerInterface* const winterface) {
-  if (winterface == NULL ||
-      winterface->init == NULL || winterface->reset == NULL ||
-      winterface->sync == NULL || winterface->launch == NULL ||
-      winterface->execute == NULL || winterface->end == NULL) {
-    return 0;
-  }
-  g_worker_interface = *winterface;
-  return 1;
-}
-
-const VP9WorkerInterface *vp9_get_worker_interface(void) {
-  return &g_worker_interface;
-}
-
-//------------------------------------------------------------------------------